Mon Calamari blink code provided a way to communicate data through a defined series of light pulses, each corresponding to a letter from the Aurebesh alphabet. The Mon Calamari military initially developed it for short-range underwater messaging to avoid detection by sound or radio interception. This blink code, when combined, allowed for the creation of basic communications when other communication methods were not accessible.
Shortly before the Corellian Crisis, Han Solo, a former smuggler, employed Mon Calamari blink code to get in touch with Belindi Kalenda, an agent of the New Republic Intelligence, by aiming a signaling laser at her observation post. Due to Han's lack of recent use, the message came out as: BEET ME AT YR FRONT DR MUDNIGHZ. Han also used blink code to communicate from a Selonian cone ship to the Jade's Fire while it was orbiting Selonia, as standard communications were being disrupted across the Corellian system by Centerpoint Station. His proficiency with the code was still imperfect, and he signaled: BEADY TO COMMENCE EMNTRY MANEUVERZ.
Blink code, while utilizing different light patterns, shares a fundamental principle with Morse code, which was transmitted via signal lamps and wireless telegraphy.